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प्रश्न
What is thermionic emission?
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उत्तर
The emission of electrons from a metal surface when heat energy is imparted to it is called thermionic emission
संबंधित प्रश्न
Answer the following questions based on a hot cathode ray tube.
State the approximate voltage used to heat the filament
Answer the following questions based on a hot cathode ray tube.
What will happen to the beam when it passes through the electric field?
In a cathode ray tube, what is the function of anode?
Give a scientific explanation.
When the radiation coming out from a certain radioactive substance is passed through an electric field, marks are found at three places on the photographic plate placed in its path.
What are cathode rays? Why are they called ‘cathode rays’? Name a material which exhibits fluorescence when cathode rays fall on it.
Why are materials of low work function preferred as thermionic cathode materials?
In a cathode ray tube state the purpose of covering cathode by thorium and carbon.
State three ways of obtaining an electron-beam.
Two radioactive sources A and B of half lives of 1 hour and 2 hours, respectively, initially contain the same number of radioactive atoms. At the end of two hours, their rates of disintegration are in the ratio of ______.
In U238 ore containing Uranium the ratio of U234 to Pb206 nuclei is 3. Assuming that all the lead present in the ore is final stable product of U238. Half life of U238 to be 4.5 × 109 years and the age of ore is ______ × 109 years. (in 109 years)
